It is well known that ruminants are in need of bioavailable essential amino acids in order to perform well as domesticated livestock. In this regard, if the animal, for example a dairy cow, does not have its minimum requirements of essential amino acids such as lysine and methionine, the animal will not produce milk at optimum yield, and its health will generally decline.
Providing essential amino acids to ruminants is not as simple as it sounds. For example, the bacteria in the rumen of a cow are known to routinely degrade amino acid sources, like lysine and methionine. Put another way, the bacteria in the rumen metabolize the amino acid source and thus "rob" the animal of the benefit of the amino acid. By the time metabolized byproduct passes from the rumen into the intestine, the amino acid is gone. The challenge, therefore, is to develop products which will allow the amino acid to be stable in the rumen, but capable of absorption when it passes from the rumen into the intestine. In other words, the essential amino acids, such as lysine and methionine, are bioavailable only in the intestine, but remain stable and therefore not metabolized in the rumen.
In the past, this problem has been recognized, and feed developers have used fats, minerals, carbohydrates and binders to protect amino acids from rumen degradation. This technology involves simple coating of the material in hopes that the coated amino acid is rumen stable. Recently, Rhone Poulenc has provided a pH-sensitive polymer coating. The theory of a pH-sensitive polymer coating for the amino acid revolves around the pH differential between the rumen and the intestine. The rumen, for example, typically has a pH of 6.5 to 7.0, and the intestine a pH of 2-3. The theory of polymer-coated essential amino acids is that something which is stable as a coating at 6.5 to 7.0 (the rumen pH), but will solubilize at more acid pH's of the intestine (pH 2-3), should be stable in the rumen, but available in the intestine.
Both technologies used in the past, i.e. coatings, such as fat coatings, and the more recently developed pH-sensitive polymer coatings, have met with limited success and have some problems. The primary problem with any product relying upon coatings of any kind for rumen stability is that the coating can become abraded during handling and during chewing by the animal. If the process handler disturbs the coating, then the amino acid becomes available to microbes in the rumen and consumed, and therefore wasted by the animal. Likewise, if the animal abrades the coating during chewing, it then becomes available in the rumen for rumen bacteria to metabolize, and is therefore also wasted to the animal. Additionally, fat-protected or coated essential amino acids rely upon the fat resistance to enzymes in the rumen that are capable of digesting the protective fat coat, and, on the other hand, the ability of digestion by enzymes post-rumenally. However, if there is not a proper balance between resistance to attack in the rumen and digestion intestine, then the amino acid benefit to the animal may be lost.
From the above description, it can be seen that there is a real and continuing need for the development of products for delivery of essential amino acids to ruminant animals in a form that allows the material to be rumen stable, i.e. resistant to degradation in the rumen, but yet after delivery from the rumen to the intestine, highly absorbable and bioavailable in the intestine. It is a primary objective of this invention to fulfill this need safely, effectively, efficiently and at low cost.
Another objective of the present invention is to provide compounds which are stable to rumen environment which do not rely upon any coating or pH-sensitive material for the stability in the rumen, and therefore are not subject to risks of handling or abrasion of the coating during chewing to wear away the coating that is needed to provide rumen stability, but intestine absorbability.
A further object of the invention is to provide a rumen-stable form of essential amino acids such as lysine and methionine which relies upon the properties of chemical bonding between the metals calcium and magnesium, and the amino acids to provide rumen stability, but intestine absorbability.
A yet further objective of the present invention is to m: provide a method of dietary supplementation of ruminant animals which provides an intestine bioavailable form of essential amino acids which is also rumen stable.
The method and means of accomplishing each of these objectives will become apparent from the detailed description of the invention which follows.